using UnityEngine;
using Shapes;

namespace AibisDream.MiniGame.Language
{
    /// <summary>
    /// 复古噪点叠加渲染器 - 在指定区域上方绘制复古显示器效果
    /// 使用 Shapes 库绘制，与粒子系统使用相同的渲染方式
    /// </summary>
    [ExecuteAlways]
    public class NoiseOverlayRenderer : ImmediateModeShapeDrawer
    {
        [Header("区域设置")]
        [Tooltip("效果覆盖的世界空间区域中心")]
        public Vector3 areaCenter = Vector3.zero;
        [Tooltip("效果覆盖的区域大小")]
        public Vector2 areaSize = new Vector2(10f, 10f);

        [Header("噪点效果")]
        [Tooltip("启用噪点效果")]
        public bool enableNoise = true;
        [Range(0f, 1f)]
        [Tooltip("噪点强度")]
        public float noiseIntensity = 0.15f;
        [Range(1, 100)]
        [Tooltip("噪点密度（点数）")]
        public int noiseDensity = 50;
        [Tooltip("噪点颜色")]
        public Color noiseColor = new Color(1f, 1f, 1f, 0.3f);
        [Range(0.001f, 0.05f)]
        [Tooltip("噪点大小")]
        public float noiseSize = 0.02f;

        [Header("扫描线效果")]
        [Tooltip("启用扫描线")]
        public bool enableScanlines = true;
        [Range(0f, 1f)]
        [Tooltip("扫描线强度")]
        public float scanlineIntensity = 0.1f;
        [Range(10, 200)]
        [Tooltip("扫描线数量")]
        public int scanlineCount = 60;
        [Tooltip("扫描线颜色")]
        public Color scanlineColor = new Color(0f, 0f, 0f, 0.15f);
        [Range(0.001f, 0.02f)]
        [Tooltip("扫描线厚度")]
        public float scanlineThickness = 0.005f;

        [Header("闪烁效果")]
        [Tooltip("启用闪烁")]
        public bool enableFlicker = true;
        [Range(0f, 0.5f)]
        [Tooltip("闪烁强度")]
        public float flickerIntensity = 0.05f;
        [Range(1f, 30f)]
        [Tooltip("闪烁频率")]
        public float flickerFrequency = 10f;

        [Header("边框暗角")]
        [Tooltip("启用边框暗角")]
        public bool enableVignette = true;
        [Range(0f, 1f)]
        [Tooltip("暗角强度")]
        public float vignetteIntensity = 0.3f;
        [Tooltip("暗角颜色")]
        public Color vignetteColor = new Color(0f, 0f, 0f, 0.5f);

        [Header("颜色失真")]
        [Tooltip("启用色差")]
        public bool enableChromaticAberration = false;
        [Range(0f, 0.05f)]
        [Tooltip("色差偏移量")]
        public float chromaticOffset = 0.01f;

        // 内部状态
        private float noiseTimer = 0f;
        private float flickerValue = 1f;
        private System.Random noiseRandom;

        private void OnEnable()
        {
            noiseRandom = new System.Random(42);
        }

        private void Update()
        {
            // 更新噪点动画
            noiseTimer += Time.deltaTime * 20f;
            if (noiseTimer > 1000f) noiseTimer = 0f;

            // 更新闪烁
            if (enableFlicker)
            {
                flickerValue = 1f - flickerIntensity * Mathf.PerlinNoise(Time.time * flickerFrequency, 0f);
            }
            else
            {
                flickerValue = 1f;
            }

            // 重新生成噪点种子
            noiseRandom = new System.Random((int)(Time.time * 60f) % 10000);
        }

        public override void DrawShapes(Camera cam)
        {
            if (!enabled) return;

            using (Draw.Command(cam))
            {
                Draw.BlendMode = ShapesBlendMode.Transparent;
                Draw.ZTest = UnityEngine.Rendering.CompareFunction.Always;

                // 绘制暗角
                if (enableVignette)
                {
                    DrawVignette();
                }

                // 绘制扫描线
                if (enableScanlines)
                {
                    DrawScanlines();
                }

                // 绘制噪点
                if (enableNoise)
                {
                    DrawNoise();
                }
            }
        }

        private void DrawNoise()
        {
            float halfWidth = areaSize.x / 2f;
            float halfHeight = areaSize.y / 2f;

            // 根据闪烁调整噪点数量
            int actualDensity = Mathf.RoundToInt(noiseDensity * noiseIntensity * flickerValue);

            for (int i = 0; i < actualDensity; i++)
            {
                // 使用随机数生成器获取位置
                float x = areaCenter.x + (float)(noiseRandom.NextDouble() * 2 - 1) * halfWidth;
                float y = areaCenter.y + (float)(noiseRandom.NextDouble() * 2 - 1) * halfHeight;
                float z = areaCenter.z;

                // 随机亮度
                float brightness = (float)noiseRandom.NextDouble();
                Color pointColor = noiseColor;
                pointColor.a = noiseColor.a * brightness * flickerValue;

                // 随机大小
                float size = noiseSize * (0.5f + (float)noiseRandom.NextDouble());

                Draw.Disc(new Vector3(x, y, z), size, pointColor);
            }
        }

        private void DrawScanlines()
        {
            float halfWidth = areaSize.x / 2f;
            float halfHeight = areaSize.y / 2f;

            // 计算扫描线间距
            float spacing = areaSize.y / scanlineCount;

            Draw.LineGeometry = LineGeometry.Flat2D;
            Draw.Thickness = scanlineThickness;

            Color lineColor = scanlineColor;
            lineColor.a = scanlineColor.a * scanlineIntensity * flickerValue;

            for (int i = 0; i < scanlineCount; i++)
            {
                float y = areaCenter.y - halfHeight + spacing * i + spacing * 0.5f;

                // 添加轻微的闪烁变化
                float lineAlpha = lineColor.a * (0.8f + 0.2f * Mathf.Sin(y * 10f + Time.time * 5f));
                Color finalColor = lineColor;
                finalColor.a = lineAlpha;

                Vector3 start = new Vector3(areaCenter.x - halfWidth, y, areaCenter.z);
                Vector3 end = new Vector3(areaCenter.x + halfWidth, y, areaCenter.z);

                Draw.Line(start, end, finalColor);
            }
        }

        private void DrawVignette()
        {
            float halfWidth = areaSize.x / 2f;
            float halfHeight = areaSize.y / 2f;

            // 绘制四个角落的暗角渐变（使用多个半透明矩形模拟）
            int steps = 8;
            for (int i = 0; i < steps; i++)
            {
                float t = (float)i / steps;
                float alpha = vignetteColor.a * vignetteIntensity * (1f - t) * flickerValue;
                Color cornerColor = vignetteColor;
                cornerColor.a = alpha * 0.3f;

                float cornerSize = Mathf.Lerp(areaSize.x * 0.3f, 0.1f, t);
                float offset = cornerSize * 0.5f;

                // 四个角落
                Vector3[] corners = new Vector3[]
                {
                    new Vector3(areaCenter.x - halfWidth + offset, areaCenter.y + halfHeight - offset, areaCenter.z),
                    new Vector3(areaCenter.x + halfWidth - offset, areaCenter.y + halfHeight - offset, areaCenter.z),
                    new Vector3(areaCenter.x - halfWidth + offset, areaCenter.y - halfHeight + offset, areaCenter.z),
                    new Vector3(areaCenter.x + halfWidth - offset, areaCenter.y - halfHeight + offset, areaCenter.z)
                };

                foreach (var corner in corners)
                {
                    Draw.Disc(corner, cornerSize, cornerColor);
                }
            }
        }

        /// <summary>
        /// 设置覆盖区域（可以从 LanguageParticleManager 获取 Canvas 区域）
        /// </summary>
        public void SetArea(Vector3 center, Vector2 size)
        {
            areaCenter = center;
            areaSize = size;
        }

        /// <summary>
        /// 设置效果强度（0-1）
        /// </summary>
        public void SetIntensity(float intensity)
        {
            intensity = Mathf.Clamp01(intensity);
            noiseIntensity = intensity * 0.15f;
            scanlineIntensity = intensity * 0.1f;
            flickerIntensity = intensity * 0.05f;
            vignetteIntensity = intensity * 0.3f;
        }

        private void OnDrawGizmosSelected()
        {
            // 在编辑器中显示效果区域
            Gizmos.color = new Color(0f, 1f, 0f, 0.3f);
            Gizmos.DrawWireCube(areaCenter, new Vector3(areaSize.x, areaSize.y, 0.01f));
        }
    }
}